SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '08352ecd6e70d2c8df8922054f46af7caf099edca71754c45dde0dfa9894e518' 
  AND token = 'OJlOTURJeeXXbgiDnWo0mtTAFAZlO35bXln1r6tSqhQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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