SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c97103f7a425604bfc4bf955c8719a05a2c8e98c371918705b21d3d345cef5c6' 
  AND token = 'pXTlN6KqmyAk0CZRrii4BOPI/MuFMx2vzn7Cg3jLxYs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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