SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '57ddd29fe79118b4b7c44ff6d41604be3053253a7a55d7528acc3eac6fb48612' 
  AND token = 'PIJPB6fYxiLmvnCt/5Y+oa+TRE597hQEGPccqKiFSqE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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