SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9c64997872f84147517a54032825bd7a267e47001dd98fdff8b0f3361703b64c' 
  AND token = 'SnqfNnvOiagzg40IRXpLhMAK7rwPDRtpQgfB6H02++c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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