SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '249e86630ddc0c5badb7739afa5ea4973e942ef34955f9095e1c1bd174b84072' 
  AND token = 'DV5lJ4Prs5rrvoVgp1/ygrCCTf/YZDEXNqG5XzMNVko=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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