SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ca6dded62243fab1f2742753b7b1c8422e010c6d0bd38be231f18bbdfc067f08' 
  AND token = 'lSJEU4GM0EnbqbvdEBWOY5Kee6KjVDoSpd0yAtqjmig=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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