SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3f5c7355a5b66ca9490c8548b0aeaabc9d2ace1014208ac03d90c0bee75f7680' 
  AND token = 'UXewJdllSkX7owVswC8j6bLZbnHCPD3TjEcWmHslTAU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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