SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4b302675275a9f220a5321c8e1d44782aa92889bd4b8592e8b069877355142fe' 
  AND token = 'MkkIDaakXYtgrA8HKI2JicAcwb96P7ISTFey1+2Ut/8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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