SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b7c499f3d982bf584261096fcfb3bde0a7aacea1822c43201bf222527a6b2df8' 
  AND token = 'seJR6P5uUJxcQdopHQSjHgGZCLeqyFeI3CL1ro7dThY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}