SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f54ad93909ba5701fc9b3a940844ff8e43a529cebd33c5febd8657968041118f' 
  AND token = 'OKHPAOcROO3SN3JY8r/4Xd67HW/s5o5EHeWFuyPSDdY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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