SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ad135608237d2e718ea7ccd80198226e28c1dd9413e582f604b0e6de2287f4dc' 
  AND token = 'RoqlLIuruzVAaYUTA3sg2LHfav60fSSAV0TUoN27ghI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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