SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '53f77baacb8c87cd2c11f588746d22b283f0910d1e7d051154492bf9a2825d07' 
  AND token = 'zIiu0xKGAmpu4nMeaBgQJjtwMSJtLEmxqs/neTR+gfY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00058

JSON explain

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