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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '714dfc2c3fb22fd9980f25969016de2bf71c82672fedb3dcbdba08c6ff29663d' 
  AND token = 'CyeuwnbccLcwiB6Y0xW1FWcMqeZ3znfBMFMeZ3Z3eSI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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