SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c6ccac83dffef1dbf7b98ef519e2dea206b707233736e5142bb37a56af46dbce' 
  AND token = 'puGAzuFkQph9BudJiKNxR8ARavNV/ZODqbhwRp69UvE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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