SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9588b761cb168fe47ed2351fc6e41d9bd5f9acbc46c80584b5dc4debeca3b209' 
  AND token = 'atqDy1f+cHPGk6MmyntqU4PvyX0JUNhH6SSAKkfa95s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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