SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f32a001b5846d782b614517218a3f70308473f81b13e3669e53fe8704ef55a8a' 
  AND token = 'NsoPQ8ZzGFnnrhVCkx0dy6T7IF7DPKQBqJpwi9CtO+k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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