SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c5a5bcd031d5ce4b45385a13ecd5c87388a5e6472fa3f4bda95457c9872d6073' 
  AND token = '96xQWCIv01EMFAylbDfyTX9eQElmcM2aiognCaqGhI0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}