SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cf84c1ecdaae544fa66a86b24e085aa1c26983a19222f1dd267cf9157a588756' 
  AND token = 'LJePM64vSMPJzEWvRbKiODGy4Uyf6kNH9bnv38d3oVs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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