SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8ef56f35852d18d7ed158768929ccbde184fd5282701db2819286fcc29b6a045' 
  AND token = 'VkkP9iTXUmozHKDWhR0uk1A/8mE0U8bpBAs34rRiTCo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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