SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c5f508a5f290e4e8d292814c159f4c7021bdb336f6e26a231001760c106c023a' 
  AND token = '/q/gbDoDxplBWM/wiUJBQOOmmwN1IHv+KJuNuwdmHfQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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