SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'db6a414de998799592d0ca7feaf5c55d3ed30feb851c900c9cd6ea068d1e80ec' 
  AND token = 'gziapWqpnrtTfxDaxfFf3n4o1Cr2iKWEjIiN12FQOyg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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