SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b64d49363da01b57180bf4cd12721f80ebf5196886149e8288429358bb1eb1ca' 
  AND token = 'jZutvz7qAwFBQ5lJhNKek9qjBUg1S4WxtqDb4t7+CeY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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