SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7bd3ff938c07e21d7af76fbc679d59ba7f7f4ee427932f312b43782dd50c373e' 
  AND token = 'iMrXfpJP6ZqauxP3fCXTJthMOwyTSnEHlaMwOU0tmY0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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