SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '58577d4b11cfe4c299804eb9dcfadd58df77b282db3031ab79516c14d3b86162' 
  AND token = 'jnvN8UMfPq//VoXRU8L4w8zjUsyRs0yuWb2smW9wmXw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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