SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'fe4fa1b7b3df8373fa80b293d3f4b3cc73e295b10d70859d24def0f4b2868cfd' 
  AND token = 'CtfggJJnbCdQ8fJGwMI/yFVfgkK9R2uMiwX0x6CAYm8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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