SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '791f9eff4e2488520bc51a2501d3126489f953d78b4505256a9578aeef944e9a' 
  AND token = 'EdccjYTVJZGvd+6tJrFLEOJMS0wlFDWNewxzDnBzYpg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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